1. Field of the Invention
This invention relates to video camera control apparatus. More particularly, the invention is concerned with apparatus for effecting technical operational control of each of a plurality of video cameras.
The expression "technical operational control", as used herein, refers to control of technical operating parameters (for example iris setting, black level, gamma and so forth) of a video camera that affect the video signal produced by the camera and that conventionally may require adjustment during operation of the camera.
2. Description of the Prior Art
FIG. 1 of the accompanying drawings shows a previously proposed video camera control apparatus 10. The illustrated apparatus 10 is intended for use in a television outside broadcast van or other vehicle, though it can also be used in a television studio. The apparatus 10 is used to control a plurality of video cameras; in the illustrated case it is shown as being connected, for example, to four cameras (camera heads or head units) 12, which may for example be Sony Corporation Type BVP 370 camera head units. Each camera 12 is subjected to control (technical operational control) by a respective remote control panel (RCP) 14, for example a Sony Corporation Type RCP 3720 remote control panel, via a respective camera control unit (CCU) 16, for example a Sony Corporation Type CCU 350 camera control unit.
Each remote control panel 14 is connected to the associated camera control unit 16 by a respective bidirectional 2400 bits/s serial data bus 18, which usually will be implemented as wiring. Each camera control unit 16 is connected to the associated camera 12 by a respective bidirectional 2400 bits/s serial data bus 20 which, depending upon equipment availability and the distance of the camera from the outside broadcast vehicle, may be implemented either as a radio link or a cable.
In use, each remote control panel 14 is controlled by an operator. One operator may control one remote control panel 14 or a group of them. For simplicity of explanation, however, it will be assumed in the remainder of this description that a respective operator controls each remote control panel 14. Each operator monitors the picture produced by the camera 12 associated with his remote control panel 14 and uses his remote control panel to adjust various different technical operational parameters of the camera, from time to time as is necessary, to ensure that the picture quality is optimum. Such control is effected, via the associated camera control unit 16, in a manner well known in the art. Thus, various different items of technical operational control data are sent to the camera 12 via the bus 20. The camera 12 responds to the control data and sends back to the remote control panel 14, via the bus 20, the camera control unit 16 and the bus 18, data (hereinafter referred to as "performance data") indicating the response of the camera to the control data. Each remote control panel 14 is provided with means for monitoring/displaying the performance data whereby the operator can monitor (as well as control) the operation of his camera by observing his remote control panel.
Optionally, the apparatus 10 may include a master setup unit (MSU) 22, for example a Sony Corporation Type MSU 350 master setup unit, which is connected to all of the camera control units 16 by a 2400 bits/s serial data bus 24. The primary purpose of the master setup unit 22 is to provide technical setup control, as opposed to technical operational control. Thus, for example, the master setup unit 22 is used at the start of a day's operations to balance all of the cameras 12 so that they produce similar outputs. Thereafter, in normal circumstances, the master setup unit 22 is not used during operation.
A problem arises in the case of the apparatus 10 of FIG. 1 if it is desired that a supervisory operator, who has overall responsibility for the technical quality of pictures from the various cameras (and, possibly, from other video signal sources) that are assembled together by the producer in the course of making a program, should have the facility of readily over-riding a decision on picture quality made by any individual operator by being able himself to effect technical operational control of any of the cameras. The same problem arises if a single operator is to be responsible for effecting technical operational control of all of the cameras; that is, if there is only a single operator as opposed to several individual operators supervised by a supervising operator. The supervisory operator or single operator could in theory be provided with the above facility, to some extent, by relatively minor modification of the apparatus 10 of FIG. 1, in that the master setup unit 22 (if provided) may include at least some of the control features of the individual remote control panels 14. However, problems arise if an attempt is made to implement the apparatus 10 as described above in such a manner as to achieve the end that the master setup unit 22 can either be used by a supervisory operator readily to over-ride a decision on picture quality made by any operator by being able himself to effect technical operational control of any of the cameras 12, or used by a single operator to effect technical operational control of all of the cameras. Thus, the master setup unit 22 is physically quite large and has many control features that are redundant as regards achieving the above end. Thus, considerations of equipment layout (siting of the master setup unit 22 for convenient operation by the supervisory operator or single operator) and ergonomics of ready use of the master setup unit (quick selection of the relevant controls from among the many controls redundant for the present purpose) mean that the master setup unit 22 is in fact ill-suited for use in achieving the above end.
A subsidiary problem resulting in the master setup unit 22 not being well suited to achieving the above end is as follows. Usually, the supervisory operator or single operator will be examining on a preview monitor that one of the various camera pictures that has been selected, by means of a preview panel (a set of switches) associated with or forming part of a vision switcher (mixer), as being the next (after that currently being outputted to air or to tape) to be outputted. Therefore, if the supervisory operator (or single operator) is to be able to do this, and if he decides that he should change a technical operational control parameter of the camera providing the preview picture, he has to accept the inconvenience and delay (and the possibility of making an error) involved in having to select on the master setup unit 22 (when very little time may be available) the camera providing the preview picture.